Inverse class F power amplifier in push-pull configuration

This paper presents an inverse class F (class F^-1) power amplifier (PA) using a 10 W gallium nitride (GaN) transistor, in push-pull configuration. This topology is similar to the current-mode class D (CMCD) PA. First a single class F^-1 PA was designed and simulated, predicting over 78% power-added efficiency (PAE). A planar half-wave balun was designed and optimized to give equal power division with 180° phase shift. A PA was simulated and fabricated containing two identical class F^-1 PAs in push-pull. The fabricated PA achieved over 75% drain efficiency at 2.46 GHz, with 42.7 dBm output. Notably, the PA achieved more than 70% drain efficiency over a bandwidth of 80 MHz.